.TH FTGAMMA 1 "May 2022" "FreeType 2.12.1"
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.SH NAME
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ftgamma \- screen gamma calibration helper
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.SH SYNOPSIS
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.B ftgamma
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.SH DESCRIPTION
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The
.B ftgamma
demo program opens a window showing series of gray stripes filled with
solid color and checkered pattern of pixels.  Your monitor's gamma value
roughly corresponds to the horizontal position where the solid and checkered
stripes are equally bright when seen from some distance.  Three brightness
targets are explored: 33%, 50%, and 67%.  If the input-output curve of your
monitor does not follow ideal power law relationship, you might observe
slightly different gamma values at different brightness levels.  It is also
possible to examine gamma values for basic colors.
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.PP
Two alternative patterns relevant to font rendering are also provided,
where slightly slanted lines are rendered using grayscale and subpixel
anti-aliasing.  In the grayscale case, the correct gamma helps to achieve
uniform perceived thickness of the lines.  The gamma value that corresponds
to vanishing moiré pattern is ideal for anti-aliased font rendering.
In the subpixel case, the correct gamma removes color fringes that remain
even after LCD filtering.
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.PP
This program does not have any options.
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.PP
This program is part of the FreeType demos package.
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